title: Use of quadrupedal step training to re-engage spinal interneuronal networks and improve locomotor function after spinal cord injury.
abstract: Can lower limb motor function be improved after a spinal cord lesion by re-engaging functional activity of the upper limbs? We addressed this issue by training the forelimbs in conjunction with the hindlimbs after a thoracic spinal cord hemisection in adult rats. The spinal circuitries were more excitable, and behavioural and electrophysiological analyses showed improved hindlimb function when the forelimbs were engaged simultaneously with the hindlimbs during treadmill step-training as opposed to training only the hindlimbs. Neuronal retrograde labelling demonstrated a greater number of propriospinal labelled neurons above and below the thoracic lesion site in quadrupedally versus bipedally trained rats. The results provide strong evidence that actively engaging the forelimbs improves hindlimb function and that one likely mechanism underlying these effects is the reorganization and re-engagement of rostrocaudal spinal interneuronal networks. For the first time, we provide evidence that the spinal interneuronal networks linking the forelimbs and hindlimbs are amenable to a rehabilitation training paradigm. Identification of this phenomenon provides a strong rationale for proceeding toward preclinical studies for determining whether training paradigms involving upper arm training in concert with lower extremity training can enhance locomotor recovery after neurological damage.
authors.affiliation: 1 Departments of Integrative Biology and Physiology, University of California, Los Angeles, California 90095, USA.
authors.forename: Prithvi K
authors.initials: PK
authors.lastname: Shah
authors.forename: Guillermo
authors.initials: G
authors.lastname: Garcia-Alias
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Choe
authors.forename: Parag
authors.initials: P
authors.lastname: Gad
authors.forename: Yury
authors.initials: Y
authors.lastname: Gerasimenko
authors.forename: Niranjala
authors.initials: N
authors.lastname: Tillakaratne
authors.forename: Hui
authors.initials: H
authors.lastname: Zhong
authors.forename: Roland R
authors.initials: RR
authors.lastname: Roy
authors.forename: V Reggie
authors.initials: VR
authors.lastname: Edgerton
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005081:Exercise Therapy / Q000295:instrumentation / Q000379:methods*; D005552:Forelimb / Q000502:physiology*; D006614:Hindlimb / Q000503:physiopathology*; D008124:Locomotion / Q000502:physiology; D009415:Nerve Net / Q000503:physiopathology*; D009474:Neurons / Q000166:cytology*; D011434:Proprioception / Q000502:physiology; D051381:Rats; D013116:Spinal Cord / Q000166:cytology* / Q000473:pathology / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology / Q000534:rehabilitation*; D013904:Thoracic Vertebrae / Q000293:injuries
keywords: motor coordination; propriospinal system; quadrupedal locomotion; rats; spinal cord hemisection